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Current status

Detailed Description

The purpose of this feature is to provide an open and flexible filesystem based single system image (SSI) linux cluster.

Currently the following filesystems can be used with fedora 11:

NFSv3, NFSv4

GFS2

Ocfs2

Ext3 as local filesystem

Basically it consists of three different software components and some small changes to the initprocess.

1. The initrd (comoonics-bootimage) to boot such a system. As it is more complex to boot from a cluster filesystem or nfs in order to use in a sharedroot configuration we need a new concept of the initrd.

2. The clustertools provide access to clusterfunctionality like querying the cluster for amount of nodes and configuration. This is organized under the software component comoonics-clustersuite.

3. The management tools for building a cdsl structure (context dependent symbolic links) and managing cdsl files. This is organized under the software component comoonics-cdsls. The cdsl concept is based on bindmounts.

Benefit to Fedora

Being able to boot multiple nodes from the same root filesystem. Enabling fedora to be a filesystem based single system image cluster.

Scope

Except from the small changes that have to be accepted for the initprocess. Everything else is already working for FC11, RHEL5 and RHEL4. So only the migration to FC12 has to be made.

How To Test

Testenvironment

We propose a preinstalled FC12 KVM machine (called installnode) which is installed as need be.

We propose that this cluster is installed on a libvirt/KVM based Maschine as a two node cluster. Libvirt is installed as standard and the network that is NATed is called *default* and has the network 192.168.122.0/24 mapped (as it is default).

There is a NFS share /mnt/virtual/nfsosr/fc12 exported on the KVM Hostmaschine as follows:

Install OSR packages

Decide how to boot the cluster

Then decide how you want to boot the cluster.

There are basically two ways to boot a open sharedroot cluster with Fedora 12.

Either you want to specify all parameters at boot time as parameters given to the boot loader.
Or you want to have those parameters set in the initrd via the cluster configuration build into the initrd.

The first way will be called "static initrd" as you might not have to change the initrd when changing the cluster.
And the second will be called "full featured initrd" as

Release Notes

Fedora now provides the ability to create filesystem based Single System Image Clusters. A server with a shareable root filesystem (only NFS3/4 up to now) is able to share the root filesystem with multiple other nodes. Hostdependent files and directories can also be managed (see Open Sharedroot).